1. Field of the Invention
The present invention relates to a walking assistance device which assists a user (person) with walking.
2. Description of the Related Art
Hitherto, as this type of walking assistance device, Japanese Patent Application Laid-Open No. 2002-191654 (hereinafter referred to as “patent document 1”), for example, discloses walking assistance equipment constituted of a thigh attachable member to be attached to a thigh and a crus attachable member which is rotatably installed to the thigh attachable member and which is to be attached to a crus. The walking assistance equipment has a drive mechanism comprised of a motor installed to the thigh attachable member, a socket installed to the crus attachable member, a ball screw threaded in a screw hole of the socket, and a flexible joint connecting a motor shaft and the ball screw. The ball screw moves into or out of the socket to change the distance between the bottom end of the flexible joint and the socket, thereby bending the crus attachable member relative to the thigh attachable member. This arrangement enables a walking-impaired person to rotationally move a knee joint and to secure stable gaits.
However, the walking assistance equipment disclosed in patent document 1 has been posing a problem of poor durability, low rotational accuracy, delayed following attributable to the flexible joint used with the drive mechanism. There has been another problem in that the crus attachable member is bent relative to the thigh attachable member by the ball screw moving into or out of the socket, so that the ball screw inevitably has a long stroke, making the ball screw long.